From the MapInfo Pro 15.0 User Guide you can see the "raster" formats supported by MapInfo Pro:
- filename.ADF (ArcInfo coverage Data File)
- filename.ASC (ASCII text file)
- filename.BIL (SPOT satellite images)
- filename.BMP (Windows bitmap)
- filename.* (CADRG format)
- filename.* (CIB format)
- filename.ECW (ECW 2.0 format handler)
- filename.EMF (Enhanced Metafile) format
- filename.FLT (Image Filter)
- filename.GEN (ADRG format)
- filename.GEN (ASRP 1.2 format)
- filename.GIF (Graphics Interchange Format)
- filename.JP2 (JPEG 2000 format)
- filename.JPG (JPEG format)
- filename.NTF (NITF format)
- filename.PCX (ZSoft Paintbrush)
- filename.PNG (Portable Network Graphics format)
- filename.PSD (Photoshop 3.0)
- filename.SID (MrSID format)
- filename.TIF (Tagged Image File Format)
- filename.TXT (Text)
- filename.TGA (Targa)
- filename.WMF (Windows Metafile format)
Now that's "plain" image formats and these don't hold any kind of information like a grid file.
For true Grid Files:
"MapInfo Pro uses the Arc Grid Handler to use and display of ESRI grid files. You will see the file extension options in the Open Table dialog box when you choose the Files of Type option Grid Image. This allows you to open both ASCII and Binary Continuous and Classified grid formats but you can only hillshade the Continuous grid files."
MapInfo Pro can also read ESRI ASCII Grid files, but they are quite slow.
If you have access to MapInfo Pro Advanced and they users who will be using these datasets are using MapInfo Pro 15.2, you could consider merging all the ESRI Grid Files into a single MRR, Multi Resolution Raster.
This would make it very fast working with the data and the users could even change the colour used on the grid very easily.